Bike as Paintbrush, City as Canvas

Michael Wallace is pretty excited about the new bike ride he's got planned. It's a tribute, he says, to the Crocodile Hunter.

"I can't wait to ride that one," he says.

How a bike ride can honor the legacy of the late animal-wrestling Australian television host is a mix of powerful and pocket-sized technology, satellites, and one very creative man who uses his bike rides to paint city-sized digital pictures on the streets of Baltimore.

Wallace has become an enthusiast of what he calls GPX – or using the Global Positioning System-tracking capability of his phone to record the path he takes on bike rides, which he pre-plans to outline massive geoglyphs and drawings. It's like a city-scaled and semi-crude Etch-a-Sketch drawing, and Wallace is the pinpoint drawing the line.

He must look almost lost zig-zagging through the city, retracing steps and abruptly turning, but it's all for the final product. His works have included a cowboy's boot, a boat pulling a waterskier, a guitar, a guy kicking a field goal and various monsters, bugs, and animals – all at least a few miles wide, and some lines more than 15 miles long. The geoglyphs have grown more elaborate with time, and some even take off on current events. Here are a few gems:

Wallace is an eighth-grade science teacher, and since 2010 he's been using his breaks from school to map out and ride more than 120 massive, multi-mile drawings on the canvas of Southeast Baltimore. He's gearing up for this summer, when he'll ride his next batch of routes, including the Crocodile Hunter ride. Within minutes of mentioning it, he's emailed over a sketch of the route.

Though Wallace isn't the originator of this activity, he is probably its most enthusiastic practitioner. On spring or summer days he can get through two or three of these "virtual geoglyphic adventures," most of which are archived on his website. In addition to his Steve Irwin ride, he's got at least 50 more planned out.

Another re-enacts a city-centered fight between the fantasy monsters Godzilla and Mothra, an especially appropriate picture to draw with the city grid.

It's pretty impressive that he's been able to develop such a level of precision and shape in his pathways. The blocky grid of Southeast Baltimore is full of 90-degree turns that can be a bit limiting. But Wallace says he's figured out how to take wide turns on corners and cut through open areas to get the curves his pictures require. He's also benefited from Patterson Park, where he's got at least a little more freedom to bend his lines. There are still some challenges, though. "I learned where every single fence is in that park," he says. On a recent ride, his path was leading right through the middle of a softball game. He sped through the outfield between innings.

To make these drawings, Wallace brings a detailed map of the city, with arrows and paths marked to keep him on track. It's not always perfect, and one missed turn can ruin what can sometimes be hours worth of work. A one-block misstep had a huge impact on an early drawing of a giant rat. "My rat ended up looking sort of like an armadillo," Wallace says.

Above: Giant Rat take one, and Giant Rat take two.

Short of these infrequent mix-ups and thunderstorm-caused GPS glitches, Wallace's rides and geoglyphs have become more smooth and polished. He's even shown some of his work in local art galleries. And he's got a lot planned for his upcoming season starting after school lets out in June. He's already psyching himself up for one especially complex ride titled "Continental Drift" – a massive representation of plate tectonics.

"I've had it planned for so long now. I look at it every once in a while and think about how it's going to go," he says. "I'm so excited for it."

Despite what will be nearly 200 drawings under his belt by the end of the summer, Wallace doesn't plan on stopping anytime soon. He says these rides have been a great way to see more of his city – and they're not bad exercise either. And even with the hard edges of the city grid, he's still able to come up with new drawings to make and new paths to ride.

"I know it's time to hang it up when I pull a map out and one doesn’t flow out of me," Wallace says. "But that hasn’t happened yet."